Reconfigurable circuits have been widely used in the semiconductor industry for field programmable gate arrays (FPGAs) and for repair of a defective memory element. The FPGA consists of a set of simple, configurable logic blocks in an array with interspersed switches that can rearrange interconnections between the logic blocks.
Reconfigurable circuits are also expected to play a significant role in three-dimensional integration technology that is being currently developed. Three-dimensional integration fabricates multilayer structures that can form a single chip combination with different functionalities. In these multilayer (and multifunctional) systems, reconfigurable circuit connection is typically needed to provide controllable logic functionality, memory repair, data encryption, as well as other functions.
A programmable via is an enabling technology for high-performance reconfigurable logic applications without the trade offs in low logic gate density and power. Phase change materials are an attractive option for this application, but to date, have drawn the most attention from semiconductor memory developers as a possible replacement to flash memory.
Certain phase change materials can be switched between conductive and resistive states through varying heat applications. Reconfigurable circuits having programmable vias with phase change materials can employ heating elements to affect this change. Coordinating the heating elements with the programmable vias still presents a challenge, however, as the accuracy, effectiveness and efficiency with which the phase change material is switched directly impact on the performance of the reconfigurable circuits.
Therefore, programmable via technology that improves switching accuracy, effectiveness and efficiency would be desirable.